The present invention relates to atomizers and nozzles for atomizers used for atomising fluids or powders carried in a stream of pressurised gas. The invention is particularly useful for introducing a medicament in the form of a medicinal fluid or powder into gas for inhalation by a patient, thereby administering a medicine to the patient. The substance may typically be a powder, a liquid or a particulate suspension. German Patent Specification DE 34 29 411 describes a nozzle for atomising, distributing and mixing fluid or powdery substances by means of a stream of gas and, in particular for producing aerosols for the purposes of inhalation. More specifically claim 1 of DE 34 29 411 claims such as a nozzle consisting of a nozzle body and an airstream control device which can be mounted on the nozzle body, wherein the stream of pressurised gas emerging centrally from the head of the nozzle through a pressurised gas duct draws in the material to be atomised from two intake ducts which are adjacent the pressurized gas ducts and are diametrically opposite one another, and wherein the airstream control device comprises a rebound bar in the outlet cone of the pressurized gas which bar is connected to a ring which can be mounted on the head of the nozzle body and is characterized in that the rebound bar (11) is shaped as a wedge in a manner known per se on its side opposite the nozzle opening (29);
in that two parallel guide surfaces (15) are provided on the ring (14) and corresponding guide surfaces (17) which are adapted to the first guide surfaces and are aligned therewith are provided on the nozzle head (16) in such a way that, when the airstream control device is mounted, the rebound bar (11) extends transversely to the connection line between the outlet openings (30, 31) of the intake ducts (5, 6); PA0 that the outer contour of the ring (14) of the airstream control, device (3) projects over the edge of the nozzle head (16) on al sides.
For reference, copies of FIGS. 1, 2 and 3 of DE 3429411 are illustrated in FIGS. 1 through 3 of the drawings indicating those components mentioned above and bearing reference numbers (11), (29), (15), (14), (17), (16), (30, (31), (5), (6) and (3).
Accurate alignment of the rebound bar is vital to the correct function of such a conventional atomizer as described in DE 34 29 411.
There are several disadvantages to the atomizers that have been used hitherto. The atomizers are often used by elderly or infirm people who meet occasionally take the atomizer apart for cleaning. When re-assembling the atomizer, the person must take care to locate the ring or tube correctly so that the rebound bar is in correct alignment as indicated above. There are usually only one or two correct orientations which will permit the device to function properly. If the atomizer is incorrectly assembled then it will not function correctly, since the bar will not correctly divert the stream of gas from the nozzle head.
Our investigations have shown that it is unnecessary to form parallel guide surfaces (15) on the ring (14) and corresponding guide surfaces (17) on the nozzle head (16) for the purpose of positioning the rebound bar (11) transversely to the connection line between the outlet openings (30, 31) of the intake ducts (5, 6).
Such a structure complicates production of moulding tools and increases not only the cost of the tooling but also the cost of the finished product.
According to one form of the present invention, a nebuliser the atomising a substance entrained into a stream of gas includes a casing, a nozzle head having at least one gas outlet and a reservoir disposed around said at least one gas outlet for receiving the substance and from which the substance is atomised by the stream of gas, means for introducing the substance to be atomised into the nebuliser, at least two holes opening into the reservoir through which the substance to be atomised is drawn by the stream of gas issuing from said at least one gas outlet and an airflow control device having a bridge bar which is locatable for interception of the gas issuing from said at least one gas outlet so as to be freely angularly displaceable for deflecting the stream of gas issuing from said at least one gas outlet across the reservoir.
Preferably the angularly displaceable airflow control device includes a tubular carries which fits on and around the nozzle head to support the bridge bar and which further includes spacing means for positioning the bridge bar in a spaced relationship relative to the reservoir and said at least one gas outlet.
It is advantageous to have as many holes leading to the reservoir a possible. This improves the flow of the substance to the reservoir. Four holes have been found to give a satisfactory flow of the substance whilst keeping the manufacturing cost down.
Preferably the nebuliser includes a source of the substance to be atomised in the form of a container.
It will be appreciated that where the reservoir is annular, the angular position of the diametrically supported rebound bar is irrelevant since it is always disposed diametrically across the reservoir and in line with the pressurized gas outlet.